US7318674B2 - Single thrust bearing fluid dynamic bearing motor - Google Patents
Single thrust bearing fluid dynamic bearing motor Download PDFInfo
- Publication number
- US7318674B2 US7318674B2 US10/263,403 US26340302A US7318674B2 US 7318674 B2 US7318674 B2 US 7318674B2 US 26340302 A US26340302 A US 26340302A US 7318674 B2 US7318674 B2 US 7318674B2
- Authority
- US
- United States
- Prior art keywords
- bearing
- thrust plate
- shaft
- thrust
- sleeve
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
- F16C33/02—Parts of sliding-contact bearings
- F16C33/04—Brasses; Bushes; Linings
- F16C33/06—Sliding surface mainly made of metal
- F16C33/10—Construction relative to lubrication
- F16C33/1025—Construction relative to lubrication with liquid, e.g. oil, as lubricant
- F16C33/106—Details of distribution or circulation inside the bearings, e.g. details of the bearing surfaces to affect flow or pressure of the liquid
- F16C33/107—Grooves for generating pressure
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C17/00—Sliding-contact bearings for exclusively rotary movement
- F16C17/04—Sliding-contact bearings for exclusively rotary movement for axial load only
- F16C17/045—Sliding-contact bearings for exclusively rotary movement for axial load only with grooves in the bearing surface to generate hydrodynamic pressure, e.g. spiral groove thrust bearings
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C17/00—Sliding-contact bearings for exclusively rotary movement
- F16C17/10—Sliding-contact bearings for exclusively rotary movement for both radial and axial load
- F16C17/102—Sliding-contact bearings for exclusively rotary movement for both radial and axial load with grooves in the bearing surface to generate hydrodynamic pressure
- F16C17/107—Sliding-contact bearings for exclusively rotary movement for both radial and axial load with grooves in the bearing surface to generate hydrodynamic pressure with at least one surface for radial load and at least one surface for axial load
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B19/00—Driving, starting, stopping record carriers not specifically of filamentary or web form, or of supports therefor; Control thereof; Control of operating function ; Driving both disc and head
- G11B19/20—Driving; Starting; Stopping; Control thereof
- G11B19/2009—Turntables, hubs and motors for disk drives; Mounting of motors in the drive
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B19/00—Driving, starting, stopping record carriers not specifically of filamentary or web form, or of supports therefor; Control thereof; Control of operating function ; Driving both disc and head
- G11B19/20—Driving; Starting; Stopping; Control thereof
- G11B19/2009—Turntables, hubs and motors for disk drives; Mounting of motors in the drive
- G11B19/2018—Incorporating means for passive damping of vibration, either in the turntable, motor or mounting
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C2370/00—Apparatus relating to physics, e.g. instruments
- F16C2370/12—Hard disk drives or the like
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49636—Process for making bearing or component thereof
- Y10T29/49639—Fluid bearing
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49636—Process for making bearing or component thereof
- Y10T29/49643—Rotary bearing
- Y10T29/49645—Thrust bearing
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49636—Process for making bearing or component thereof
- Y10T29/49696—Mounting
Definitions
- the invention relates generally to the field of fluid dynamic bearings, and more particularly to a design which includes a simplified thrust bearing design.
- Disc drive memory systems have been used in computers for many years for storage of digital information.
- Information is recorded on concentric tracks of a magnetic disc medium, the actual information being stored in the forward magnetic transitions within the medium.
- the discs themselves are rotatably mounted on a spindle, while the information is accessed by read/write has generally located on a pivoting arm which moves radially over the surface of the rotating disc.
- the read/write heads or transducers must be accurately aligned with the storage tracks on the disk to ensure proper reading and writing of information.
- the discs are rotated at very high speeds within an enclosed housing using an electric motor generally located inside the hub or below the discs.
- spindle motors typically have had a spindle mounted by two ball bearing systems to a motor shaft disposed in the center of the hub.
- the bearings are spaced apart, with one located near the top of the spindle and the other spaced a distance away. These bearings allow support the spindle or hub about the shaft, and allow for a stable rotational relative movement between the shaft and the spindle or hub while maintaining accurate alignment of the spindle and shaft.
- the bearings themselves are normally lubricated by highly refined grease or oil.
- the conventional ball bearing system described above is prone to several shortcomings.
- First is the problem of vibration generated by the balls rolling on the bearing raceways. This is one of the conditions that generally guarantee physical contact between raceways and balls, in spite of the lubrication provided by the bearing oil or grease.
- bearing balls running on the generally even and smooth, but microscopically uneven and rough raceways transmit the rough surface structure as well as their imperfections in sphericity in the vibration of the rotating disc.
- This vibration results in misalignment between the data tracks and the read/write transducer.
- This source of vibration limits the data track density and the overall performance of the disc drive system. Vibration results in misalignment between the data tracks and the read/write transducer. Vibration limits therefore the data track density and the overall performance of the disc drive system.
- lubricating fluid either gas or liquid
- Liquid lubricants comprising oil, more complex fluids, or other lubricants have been utilized in such fluid dynamic bearings.
- the reason for the popularity of the use of such fluids is the elimination of the vibrations caused by mechanical contact in a ball bearing system, and the ability to scale the fluid dynamic bearing to smaller and smaller sizes.
- the present invention is intended to provide a fluid dynamic bearing assembly especially useful in a high speed spindle motor assembly.
- a further advantage of the present invention and objective thereof is to provide an improved stiffness to power ratio in a fluid bearing arrangement.
- the present invention is intended to provide a fluid bearing assembly which diminishes to some extent the power requirements in a thrust plate fluid bearing design.
- a typical dynamic bearing design which comprises a ring shaped or circular thrust plate mounted at or near the end of a shaft, the shaft defining together with a surrounding sleeve a journal bearing by providing grooves on only one of the two surfaces facing the gap between the shaft and sleeve.
- the traditional upward thrust bearing defined between the lower face of the thrust plate and the facing surface of the sleeve is maintained; but no grooves are on the surface of the thrust plate distant from the shaft and a facing counterplate surface.
- the journal bearing is defined to have an asymmetry so that a bias force pressure along the surface of the shaft toward the thrust plate is established.
- journal groove asymmetry pumping action toward the shoulder or thrust plate, together with the single grooved thrust bearing, is sufficient to establish a constant pressure between the distal surface of the thrust plate and the facing counterplate, as well as between the groove thrust plate and the facing shoulder surface.
- the gap between the shaft adjacent thrust plate surface and the facing sleeve surface should be designed to be relatively small, (in a range from about 2 to 12 microns.
- the ungrooved gap between the counterplate and the facing thrust plate surface and end surface can be relatively large and lower precision, since this interface is not acting as a pressure generating bearing; rather, this gap and the facing surfaces primarily act as a shock displacement limiter, shaft landing zone and journal asymmetry pressurization region subject to pressurization by the journal bearing.
- the above preferred embodiments utilize journal asymmetry pumping pressure acting against the surfaces of the thrust plate and especially the ungrooved thrust plate gap as a constant force axially biasing the rotor or shaft such that the grooved surface of the thrust gap closes until axial force equilibrium is achieved.
- the grooved section of the thrust plate surface can be adjusted to provide additional asymmetry pressure acting on the thrust plate surface.
- the thrust bearing would be a chevron pattern or a spiral or similar to adds pressure to the asymmetric pressure acting on the thrust plate face, although a spiral design, in a preferred form, would include a circulation path across the thrust plate inner diameter.
- FIG. 1 is an elevation view and cross section of a computer hard disk spindle motor assembly taken along the axis of rotation of the spindle motor assembly;
- FIG. 2 is a plan view of one of the surfaces of a single thrust bearing
- FIGS. 3A , 3 B and 3 C are vertical sectional views of the shaft, sleeve, thrust plate and counterplate which are used to explain preferred embodiments of the present invention.
- FIG. 1 is a cross section through one embodiment of a spindle motor assembly which may readily be adapted to incorporate a fluid dynamic bearing arrangement according to the present invention. More specifically, the spindle motor shown in FIG. 1 is of a fixed shaft design; whereas FIGS. 3A and 3B are used to further illustrate the present invention are both of a rotating shaft design. It will be apparent to a person of skill in the art that the present invention is readily useful with both either a fixed shaft or a rotating shaft design.
- FIG. 1 illustrates a cross section through one embodiment of a spindle motor which may be adapted to incorporate a fluid dynamic arrangement according to the invention.
- the spindle motor assembly comprises a base 12 and a hub assembly 13 .
- a shaft 14 is mounted to the base 12 by a nut 16 .
- the dual reference numbers are used because the journal bearings are typically in two sections.
- the journal bearings 28 , 30 each include a grooved surface. The grooved surfaces may be provided either on the outer surface of the shaft 14 , or the inner bore surface of the journal sleeve 26 , and journal 28 is typically asymmetric.
- a thrust plate 32 is press fitted or formed or otherwise attached to an end of the shaft 14 and extends transversely to the shaft 14 .
- the thrust plate 32 is circular in form, the thrust plate 32 defines a first axial thrust surface 33 which, together with a facing sleeve thrust surface 35 extending transverse to the journal bearing defines a first fluid dynamic thrust bearing 34 in the gap between the two surfaces.
- the thrust surface 35 at bearing 34 extends transversely to the journal at 30 , and the thrust bearing gap is connected to that journal bore.
- a counterplate 36 is press fitted to or otherwise supported by the journal sleeve 26 adjacent the thrust plate surface 37 which is distal from the journal bearing 28 , 30 .
- the counterplate 36 has a surface 39 which corporates with the thrust plate surface 37 to define a gap in which fluid is maintained during rotational operation of the shaft and sleeve. Therefore, the counterplate 36 is sealed to the journal sleeve 26 by a O-ring 40 or other means to prevent any loss of the fluid which appears in the gap between counterplate and thrust plate.
- the gap 38 between the counterplate and the distal thrust plate surface is typically about 10 microns or larger; it is at the larger end of bearing gaps, or perhaps even larger because its criticality to creating axial force is not necessary. Rather, the surfaces are relatively smooth and do not require exact smoothness or polishing because of the lack of grooves. Rather, the fluid in this gap is provided primarily to support relative rotation between the shaft sleeve and counterplate.
- the gap between the thrust plate adjacent to the journal bearing is at the small end of typical thrust plate bearing gaps, because of the fact that a groove pattern is provided on this surface, and it is necessary and desirable to provide both high axial and angular stiffness.
- the hub assembly 13 is rotated with respect to the base 12 in use by means of an electromagnetic motor.
- the electromagnet motor comprises a stator assembly 52 mounted to the base 12 , and a magnet 54 mounted to the journal sleeve 26 .
- the hub assembly 13 which generally comprises the journal sleeve 26 , hub 50 , counterplate 36 , and first and second porous lubricant reservoirs 42 and 44 , is supported for rotation relative to the base 12 and shaft 14 on hydrodynamic bearings 28 , 30 , 34 , and 38 .
- FIG. 2 illustrates a plan view of one of the surfaces of a hydrodynamic thrust bearing.
- the illustrated hydrodynamic bearing surface generally indicated by the numeral 60 , comprises a series of alternating grooves 62 and lands 64 .
- Each groove 62 and land 64 comprises a leg which extends outward from the inner radius 66 of the hydrodynamic bearing surface 60 and a leg which extends inward from the outer radius 68 of the hydrodynamic bearing surface 60 .
- the two legs in a point at an intermediate radius 70 .
- the plurality of grooves 62 and lands 64 together form a curved herringbone pattern as illustrated in the figure.
- a hydrodynamic thrust bearing is formed when the bearing surface 60 is placed adjacent to an opposed bearing surface with a film of lubricant between the two surfaces.
- the bearing surface 60 is rotated in the direction 72 , that the, against the herringbone pattern, the grooves 62 and lands 64 tend to draw lubricant from the inner and outer radii 66 and 68 towards the points of the herringbone pattern at 70 . This creates a radial pressure distribution within the lubricant which serves to keep the bearing surfaces apart under external loading.
- the pressure distribution across the hydrodynamic bearing can be varied.
- the pressure in the bearing lubricant is greater at the inner radius 66 than at the outer radius 68 during operation, a new flow of lubricant from the inner radius 66 to the outer radius 68 will result, and vice versa.
- This can be done, for example, by having the intermediate radius 70 , at which the points of the herringbone (or spiral) pattern are located, closer to the outer radius 68 .
- the pressure distribution amplitude across the hydrodynamic bearing can be varied by various means including altering the design of the grooves. The significance of having a net flow of lubricant across the bearing surface is discussed below.
- the grooves 62 and lands 64 may be formed in the hydrodynamic bearing surface by any number of means including, for example, chemical machining or stamping.
- a hydrodynamic journal bearing such as the hydrodynamic journal bearings 28 and 30 illustrated in FIG. 1 .
- the pattern of the grooves and lands of the hydrodynamic journal bearings 28 , 30 can be arranged to create a net flow of lubricant in a direction along the longitudinal axis of the shaft 14 , i.e. towards or away from the base 12 ; in this case it is toward the thrust bearing.
- a hydrodynamic bearing is not limited to the use of a herringbone pattern of grooves 62 and lands 64 .
- a spiral or sinusoidal pattern may be used as an alternative to the herringbone pattern.
- the herringbone pattern is however preferred for thrust bearing arrangements as it generates a pressure distribution across the bearing surface which provides improved bearing rocking stiffness.
- Bearing rocking stiffness is a measure of the ability of a thrust bearing to resist rotation of the bearing surfaces relative to one another about an axis traverse to the axis of rotation of the thrust bearing.
- the hub assembly 13 (generally comprising the journal sleeve 26 , counterplate 36 , porous lubricant reservoirs 42 and 44 and the hub sleeve 50 ) is rotated relative to the base 12 by means of an electromagnetic motor comprising stator assembly 52 and magnet 54 .
- the hub assembly is supported for smooth rotation on the shaft 14 and thrust plate 32 by the pressures generated in the lubricant at the hydrodynamic bearings 28 , 30 , 34 and 38 .
- the present design seeks to minimize the power consumption which is typically associated with the use of a two-sided thrust bearing.
- This power consumption comes from the fact that in the typical design which uses a thrust plate with a bearing on either side of the thrust plate provides the desired level of axial stiffness.
- the viscosity of the fluids used in the gap is relatively high at low temperatures, thus the drag on the grooved surfaces of a dual thrust bearing design i.e. one with grooves on both axially facing surfaces is quite high.
- the approach herein of using one rather than two fluid dynamic thrust bearings will reduce the power consumed.
- the journal bearing comprises grooves along one of the shaft 20 or the facing sleeve 26 .
- the journal bearing is in two sections; in the present design, shown in FIGS.
- the design is modified so that a net pumping action along the journal bearing toward the thrust plate is established.
- This net pumping is referenced by the arrow 302 drawn along the shaft 300 , and can be established according to the skill in the art in any of the number of ways.
- One approach is to modify the design of the grooves which are used to establish the journal bearing along the shaft. Alternatively, in an instance where two sets of grooves are defined along the journal bearing, one of these, typically the journal bearing most distant from the thrust plate 28 is made longer than the other set of grooves. This alteration produces an asymmetric pumping action toward the thrust plate 304 .
- the journal asymmetry pumping pressure 302 can be set to act as a constant force to axially bias the shaft 300 and thrust plate 304 relative to the surrounding sleeve and counterplate by pumping sufficient fluid into the gap 310 between the thrust plate surface 312 and the sleeve shoulder 313 which is not shown; and further pumping fluid into the gap 320 between the thrust plate surface 322 distal from the shaft and the facing surface 323 on the counterplate so that a constant journal asymmetry pressure 330 , and 332 (the pressures preferably being substantially equal) is achieved to produce a force equilibrium which allows for free rotation of the shaft and thrust plate relative to the sleeve and counterplate.
- pressure times surface area equals force.
- the net pressure 340 times the thrust plate surface area is substantially equal to the journal asymmetric pressure times the shaft end surface area.
- a thrust bearing is established which provides the generally triangular additional force as a function of gap represented by the regions 340 , 342 of the pressure diagram ( FIG. 3A ) to suspend and maintain the separation of the thrust plate 304 from the adjacent surfaces.
- the grooved thrust plate region not only contributes to the maintenance of the separation of that shoulder of that surface from the facing shoulder, but referring to FIG. 3B it can be seen that the shaft asymmetry pressure 302 contributes primarily to (and will typically be equal to) the pressure 351 which is created at the distal end of the shaft 350 which faces the counterplate 352 .
- the pressure in the adjacent regions generally indicated at 354 , 356 ( FIG. 3A ) is primarily established by the pumping effect of the thrust plate bearing 312 .
- the thrust bearing 312 would typically be a chevron pattern or an outward spiral, as is well known in the art, which can add to the pressure on the gap surface 312 as well as contributing to the pressure established at the opposed thrust plate regions 354 , 356 .
- This grooved thrust bearing can be designed to operate at a relatively small effective gap 310 , such that a high axially and angular stiffness and efficiency can be achieved.
- the ungrooved gap 320 between the shaft face and the counterplate 312 as well as between the thrust plate surface 322 and the counterplate 312 can be larger and lower precision than in normal dual thrust plate bearings of the prior art.
- the pressure in this gap 320 is a substantially constant pressure independent of thrust gap that is equal to journal asymmetry pressure. This region now acts primarily as a shock displacement limiter, shaft landing zone and journal asymmetry pressurization region.
- the single thrust bearing with a reduced diameter which may be used pursuant to the present design, will consume less power than the dual thrust bearing design of the known art, because of the use of one thrust gap instead of two. Further, the angular stiffness which is necessary in designs such as disc drives will be achieved through the reduced bearing gap of the single thrust bearing adjacent the journal bearing.
- journal asymmetry pressure is utilized as a constant thrust bias force, other sources of biasing such as magnetic magnets or the like are not needed, thereby eliminating such parts and the tolerances associated therewith.
- FIG. 3C An alternative embodiment is shown in FIG. 3C ; the primary distinction between this and other embodiments is the use of a circulation hole or holes 370 which are defined across the thrust plate inner diameter.
- a circulation hole or holes 370 which are defined across the thrust plate inner diameter.
- an asymmetric journal pressure A is developed axially along shaft 372 , biased toward thrust plate 374 . This pressure appears as pressure A against both the grooved surface 376 and the ungrooved surface 378 of thrust plate 374 .
- the grooves (not shown) on surface 376 generate a net spiral thrust pressure T represented by the triangular region biased on dotted line 381 .
- T*TA A * SA (wherein A * TA cancels i.e. the top vs. bottom pressures).
- the circulation holes 370 can be used with chevron or spiral grooves, but are especially necessary with a spiral groove pattern.
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Sliding-Contact Bearings (AREA)
Abstract
Description
Claims (9)
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/263,403 US7318674B2 (en) | 2002-03-13 | 2002-10-02 | Single thrust bearing fluid dynamic bearing motor |
US11/933,212 US7856719B2 (en) | 2002-03-13 | 2007-10-31 | Single thrust bearing fluid dynamic bearing motor |
US12/950,383 US8732954B2 (en) | 2002-03-13 | 2010-11-19 | Single thrust bearing fluid dynamic bearing motor |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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US36407202P | 2002-03-13 | 2002-03-13 | |
US10/263,403 US7318674B2 (en) | 2002-03-13 | 2002-10-02 | Single thrust bearing fluid dynamic bearing motor |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/933,212 Continuation US7856719B2 (en) | 2002-03-13 | 2007-10-31 | Single thrust bearing fluid dynamic bearing motor |
Publications (2)
Publication Number | Publication Date |
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US20030174916A1 US20030174916A1 (en) | 2003-09-18 |
US7318674B2 true US7318674B2 (en) | 2008-01-15 |
Family
ID=28041867
Family Applications (4)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/214,980 Abandoned US20030185472A1 (en) | 2002-03-13 | 2002-08-07 | Single thrust bearing fluid dynamic bearing motor |
US10/263,403 Expired - Fee Related US7318674B2 (en) | 2002-03-13 | 2002-10-02 | Single thrust bearing fluid dynamic bearing motor |
US11/933,212 Expired - Lifetime US7856719B2 (en) | 2002-03-13 | 2007-10-31 | Single thrust bearing fluid dynamic bearing motor |
US12/950,383 Expired - Lifetime US8732954B2 (en) | 2002-03-13 | 2010-11-19 | Single thrust bearing fluid dynamic bearing motor |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/214,980 Abandoned US20030185472A1 (en) | 2002-03-13 | 2002-08-07 | Single thrust bearing fluid dynamic bearing motor |
Family Applications After (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/933,212 Expired - Lifetime US7856719B2 (en) | 2002-03-13 | 2007-10-31 | Single thrust bearing fluid dynamic bearing motor |
US12/950,383 Expired - Lifetime US8732954B2 (en) | 2002-03-13 | 2010-11-19 | Single thrust bearing fluid dynamic bearing motor |
Country Status (2)
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US (4) | US20030185472A1 (en) |
WO (1) | WO2003079347A1 (en) |
Cited By (3)
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US20110001282A1 (en) * | 2008-02-29 | 2011-01-06 | Thk Co., Ltd. | Rotary table device provided with cooling structure and rotary bearing provided with cooling structure |
US20110033143A1 (en) * | 2009-08-04 | 2011-02-10 | Alphana Technology Co., Ltd. | Disk drive device improved in anti-vibration characteristic |
US20110064342A1 (en) * | 2002-03-13 | 2011-03-17 | Seagate Technology Llc | Single thrust bearing fluid dynamic bearing motor |
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JP2004340368A (en) * | 2003-04-22 | 2004-12-02 | Nippon Densan Corp | Hydrodynamic bearing and its manufacturing method, device for manufacturing shaft member for hydrodynamic bearing, spindle motor, and recording disc driving apparatus |
US7423839B2 (en) * | 2004-03-19 | 2008-09-09 | Seagate Technology Llc | Low power support pads for moment loading and associated methods |
JP5308885B2 (en) * | 2009-03-25 | 2013-10-09 | 株式会社日立メディアエレクトロニクス | Optical pickup device |
US8411389B1 (en) | 2010-06-29 | 2013-04-02 | Western Digital Technologies, Inc. | Disk drive fluid dynamic bearing spindle |
US9181978B2 (en) * | 2013-04-10 | 2015-11-10 | Seagate Technology Llc | Grooved thrust bearing |
US9097279B2 (en) | 2013-06-20 | 2015-08-04 | Seagate Technology Llc | Rotating shaft top cover attached motor |
US10422373B1 (en) | 2018-04-04 | 2019-09-24 | General Electric Company | Machine thrust bearing assembly |
DE102019106064A1 (en) * | 2019-03-11 | 2020-09-17 | Minebea Mitsumi Inc. | Spindle motor |
US11353057B2 (en) | 2019-12-03 | 2022-06-07 | Elliott Company | Journal and thrust gas bearing |
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US20110064342A1 (en) * | 2002-03-13 | 2011-03-17 | Seagate Technology Llc | Single thrust bearing fluid dynamic bearing motor |
US8732954B2 (en) * | 2002-03-13 | 2014-05-27 | Seagate Technology Llc | Single thrust bearing fluid dynamic bearing motor |
US20110001282A1 (en) * | 2008-02-29 | 2011-01-06 | Thk Co., Ltd. | Rotary table device provided with cooling structure and rotary bearing provided with cooling structure |
US8439338B2 (en) * | 2008-02-29 | 2013-05-14 | Thk Co., Ltd. | Rotary table device provided with cooling structure and rotary bearing provided with cooling structure |
US20110033143A1 (en) * | 2009-08-04 | 2011-02-10 | Alphana Technology Co., Ltd. | Disk drive device improved in anti-vibration characteristic |
US8506168B2 (en) * | 2009-08-04 | 2013-08-13 | Samsung Electro-Mechanics Japan Advanced Technology Co., Ltd. | Disk drive device improved in anti-vibration characteristic |
Also Published As
Publication number | Publication date |
---|---|
US20030174916A1 (en) | 2003-09-18 |
US20110064342A1 (en) | 2011-03-17 |
US20080056105A1 (en) | 2008-03-06 |
US20030185472A1 (en) | 2003-10-02 |
US8732954B2 (en) | 2014-05-27 |
WO2003079347A1 (en) | 2003-09-25 |
US7856719B2 (en) | 2010-12-28 |
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